Analog telephone networks use circuit-switched networks designed to provide voice communications. One characteristic of a circuit-switched network is that they are connection-oriented, wherein a hard-wired information path must exist before information will transmit. Further, circuit-switched networks reserve the full bandwidth of the information over the duration of the transmission. As a result, the transmission has a guaranteed QoS on the network, because the telephone call does not share its dedicated circuit with other telephone calls. This dedicated circuit insures high voice quality, continuous information transmission, and minimum delay.
Unlike analog telephone networks, which are designed to serve the needs of voice communications, data networks, such as the Internet, are used to facilitate data communications. Voice over Internet Protocol (VoIP) is a method in which voice communication may be carried out over data networks, such as the Internet, by processing voice into Internet Protocol (IP)-formatted packets. VoIP transmits digital packets of encoded voice information over shared packet-based circuits. In contrast to analog circuit-switched networks that are designed for constant bit-rate circuit applications over a continuous transmission path, packet-switched networks are designed for variable bit-rate applications transmitted over a series of routers and paths.
Problems can occur when transmitting voice communication over a packet-switched network. For example, because there is no dedicated transmission path, large delays in transmission can occur as a result of the packet transfer between routers and different physical transmission paths. When a significant amount of data is transmitted over a packet-based circuit there may be a decrease the QoS due to bandwidth sharing that must occur to facilitate communication over a shared path. The decrease in QoS may manifest as delay, jitter, and/or distortion of the transmission. Such effects impact the audio quality of the system and, accordingly, the satisfaction of the users on a communication network.
Known methods of determining QoS for an end-to-end transmission between two callers enable a communication service provider to monitor the QoS characteristics of the communications between the two callers at the callers' physical premises. That is, hardware may be installed at consumer sites and calls between consumers may be monitored for quality. In one known method of determining QoS, an end-to-end transmission is defined over a single provider network or multiple provider networks. In either case, the QoS is determined from a transmitter to a receiver, or end-to-end transmission. Furthermore, these known methods do not facilitate monitoring QoS for a portion of a network facilitating a call when the call is routed over multiple providers' networks. Additionally, such QoS monitoring configurations mandate that a single entity has control of the consumer premises equipment (CPE) at all customers' sites between which the QoS is to be monitored.